The compounds of formula (I) above are macrocyclic lactones, the structures of which have been mentioned in the prior art, typically in the context of synthetic studies aimed at the preparation of large carbocycles or in reasons where these lactones are intermediate products which are chemically converted into structure related end products, with out being properly characterized.
U.S. Pat. No. 3,890,353, for example, describes a process for the preparation of saturated macrocyclic lactones having 14 to 17 carbon atoms in the ring, via complete hydrogenation of intermediate mixtures of saturated and unsaturated lactones. In the context of this disclosure, there is described an intermediate mixture of 14-methyl-14-tetradec-(11 and 12)-enolide and 14-methyl-14-tetradecanolide, the hydrogenation of which leads to the latter. This mixture is disclosed purely as a chemical intermediate in said process, and there is no teaching of the chemical or physical characteristics of 14-methyl-14-tetradec-(11 and 12)-enolide, its isomeric composition for instance remaining totally unknown.
A. G. Cameron et al., on the other hand, fully characterize (E)- and (Z)-12-tetradecen-14-olide, used as intermediates in the context of Ireland enolate Claisen rearrangement type reactions (see J. Chem. Soc. Perkin Trans. I, 1986, 161).
This article is however silent as regards any other potential use or property of the described tetradecenolides.
It is also known in the art that some higher homologues of compounds (a) are prized perfume ingredients. In this context, one can cite for example 15-pentadecanolide, a saturated higher homologue, better known under the tradename of Exaltolide.RTM. (trademark of Firmenich SA. Geneva. Switzerland), which is described in the U.S. Patent cited above.
A more recent document EP-BI-424 787, describes useful perfuming ingredients formed of (11,12)-pentadecen-15-olides.
It is, therefore, with great surprise, that we have discovered that, in spite of the structural teachings cited above, there is no suggestion in the prior art of the object of the present invention, i.e. the advantageous application of the newly discovered and unexpected fragrance properties of lactones (I) and their mixtures.